Spotlight on Asteroid Hyalosis: A Clinical Perspective

Figures & data

Figure 1 Appearance of asteroid hyalosis in slit-lamp with direct focal illumination (A) and retinal examination here seen using a fundus photography (B).

Figure 2 Asteroid hyalosis is seen as numerous hyperreflective foci in the vitreous in cross-sectional optical coherence tomography (OCT) scans (A) as well as 3D OCT (B), and as small round hyperechoic elements in the vitreous in B-scan ultrasonography (C).

Table 1 Differential Diagnoses of Asteroid Hyalosis

Differential Diagnosis	Symptoms	Clinical Features and Diagnosis	Clinical Work-Up	Treatment Needed?
Common conditions
Posterior vitreous detachment.	Floaters (spider webs, strings, transparent ring).	Fundus examination will reveal the posterior vitreous detachment. A Weiss ring may be visible. The hyperreflective delineation of the vitreous may no longer be visible on optical coherence tomography. B-scan ultrasonography may reveal a thin hyperechoic line corresponding to the posterior vitreous.	The majority of these cases are mild without any complications. However, retinal breaks or tears are important to identify for prophylactic laser therapy to prevent retinal detachment. Some cases may even present with rhegmatogenous retinal detachment.	Yes, cases with retinal complications.
Vitreous hemorrhage	Sudden onset of floaters and blurred vision. A more severe bleeding will give rise to a severe vision loss.	Examination of anterior vitreous reveals cells that are predominantly in a red hue. Fundus examination may not be possible due to the extent of the hemorrhage. B-scan ultrasonography will show heterogenous echogenic material in the vitreous.	Determine underlying pathology to the extent it is possible to treat what needs and can be treated. Diagnoses to consider include proliferative diabetic retinopathy, posterior vitreous detachment with complications, venous occlusion, any vascular or inflammatory with ischemia and retinal neovascularization, retinal breaks, retinal tears, retinal detachment, and tumor.	Yes
Vitritis	Blurred vision, floaters, pain, photophobia, and hyperemia.	Examination of anterior vitreous reveals cells that are in a white hue. Some cases are also accompanied by cells and flare in the anterior chamber. Vitreous condensation, vitreous haze, snowballs, and snowbanking may be seen.	Work-up protocol for uveitis.	Yes
Rare conditions
Synchysis scintillans	Asymptomatic condition in a blind eye with long history of chronic hemorrhage or uveitis.	Examination of the vitreous reveals golden/brown colored crystals which sink inferiorly when the eye is immobile.	Underlying pathology is usually known when synchysis scintillans is present, as the eye is usually blind due to a long history of chronic hemorrhage or uveitis.	No
Amyloidosis	Blurred vision, floaters, and photophobia.	Examination of the vitreous will reveal opacities with a granular appearance in the early stages. Later, the opacities will aggregate to a glass wool-like appearance. Exudates, peripheral retinal neovascularization, and cotton wool spots can be observed upon retinal examination.	Vitreous sampling allows a pathological examination that reveals a fibrillar morphology and the amyloid proteins will reveal their specific histological characteristics when Congo red stain is applied. Search for the extent of amyloid infiltration: orbit, eyelids, conjunctiva, cornea, iris, and also consider a work-up plan for potential extraocular manifestations. Further multidisciplinary work-up is often needed.	Yes
Endophthalmitis	Blurred vision, pain, hyperemia. Fever can be present if endogenous endophthalmitis.	Anterior chamber inflammation and hypopyon. Examination of anterior vitreous reveals cells that are in a white hue. Many cases are also accompanied by eyelid edema and conjunctival congestion.	Aqueous and vitreous sampling and microbiology are important aspects of the work-up.	Yes
Malignancy e.g. lymphoma	Floaters, blurred vision.	Examination of anterior vitreous reveals cells that are in a white hue often with a dense posterior vitreous membrane. This condition can be difficult to differentiate from vitritis. Large, multifocal, yellow-colored chorioretinal lesions may be present upon fundus examination.	Diagnostic vitrectomy with flow cytometry and pathological examination of a vitreous sample is necessary for the diagnosis. Further multidisciplinary work-up is often needed.	Yes

Figure 3 Scanning laser ophthalmoscopy-based systems such as OPTOS may enable retinal examination to a certain degree.